Gyroscope



.atented Jan. 7, 1941 PATENT OFFICE GYROSCOPE Robert Alkali, Paris,France Application October 8, 1938, Serial No. 234,fi35 In FranceOctober 22, 1937 Claims.

The present invention relates to gyroscopes, and more particularly togyros-copes oi the type designed for use as gyro verticals or artificialhorizons on board of dlrlgible crait.

it is a known i'act that the spin axis of a gyroscope has a tendency tocreep or process from its normal position due to friction in thebearings thereof, and in the case of gyro verticals or artificialhorizons, ii the gyroscope is slightly ill pendulous, the vertical spinaxis thereol? will be caused to precess out of the vertical by theaction of acceleration or deceleration iorces produced when there is anincrease or decrease in the speed of the craft on which the gyroscope isit mounted. v

Various means have been provided heretofore for maintaining the axis ofthe gyroscope in normal position or to return the same to such normalposition when said spin axisis deviated there- W irom.

in the case of gyro verticals or artificial horieons, these are usuallyprovided with some form oi gravitational control means, generally callederecting means, which cause the spin axis of the gyroscope to come torest in a vertical position and to maintain it in this vertical positioneven though external acceleration forces may be acting on the gyroscopetending to deviate said axis i'rom the vertical position.

One of the objects of the present invention is to improve the qualitiesof precision and sensitivity of gyroscopes and to make them moresuitable tor use on board of dirigible craft such as aircrait.

5 Another object of the invention is to provide novel and improvederecting means for gyroscopic devices of the type referred to above.

another object of the invention is to provide novel erecting means for agyro vertical or artificial horizon, comprising a single gravitationalcontrol means mounted for rotation and/or angular movement about thevertical spin axis of the gyroscope, and effective to control air jetmeans on said gyroscope to produce a stabilizing 4 torque on thegyroscope when the axis thereoi departs from the vertical, therebycausing said spin axis to return to its normally vertical position.

a iurther object of the invention is to provide novel and improvederecting means for gyroscopes oi the class described, comprising air jetmeans mounted on the gyroscope and angularly adjustable with respect tosaid gyroscope.

it still further object is to provide novel erectta ting means for gyroverticals 0r artificial horizons, comprising airjet means angularlyadjustable with respect to the gyroscope about an axis parallel to orcoincident with the spin axis of the gyroscope.

it. further object is to provide novel erecting means for gyro verticalsor artificial horizons, comprising angularly adjustable air jet meansmounted on the gyroscope for rotation and/or angular movement about thespin axis of the gyroscope or about an axis parallel to said spin axis,and controlled by. acceleration responsive means.

it. still further object of the invention is to provide, in combinationwith the gyroscope of a gyro vertical or artificial horizon, novelerecting means comprising air jet means angularly adjustable about thespin axis of the gyroscope or about an axis parallel to said spin axis,and acceleration responsive means responsive to acceleration componentsperpendicular to the spin axis of the gyroscope for controlling said airjet means.

it further object of the invention is to provide, in combination with agyroscope, novel erecting mechanism comprising angularly adjustable airjet means controlled by acceleration responsive means which cause saidair jetrneans to be adjusted at any instant so as to direct the air jetin a direction at right angles to the plane containing both the axisabout which said air jet means are adjustable and the accelerationcomponent perpendicular to said axis.

A still further object of the invention is to provide, in combinationwith a gyroscope, novel erecting mechanism comprising angularly adjustable air jet means controlled by acceleration responsive means andin which the frictional resistance oi the acceleration responsive meansis automatically compensated by the action of the air jet means.

A further object of the invention is to provide, in combination with agyro vertical or artificial horizon of the type having a gyroscopependulously mounted, novel erecting mechanism comprising angularlyadjustable air jet means controlled by acceleration responsive means andin which the torque on the gyroscope resulting from acceleration forcesacting on the pendulous gyroscope is automatically compensated by theaction of said air jet means.

The above and other objects and features of the invention will appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawings whereinseveral embodiments oi the invention are illustrated by way of example.It is to be expressly understood, however, that the drawings are forpurposes of illustration and description only and are not designed as adefinition of the limits of the invention, reference being had for thispurpose to the appended claims.

In the drawings, wherein like reference characters refer to like partsthroughout the several views:

Fig. 1 is a vertical section of a gyroscope embodying one form of novelerecting means of the invention;

Fig. 1a is a top plan view of the gyroscope shown in Fig. 1;

Figs. 2a, 2b, 2c, and 201 show diagrammatically various relativearrangementsof certain parts of the gyroscope shown in Fig. 1, as viewedfrom the top thereof;

Fig. 3 is a detail vertical section of another embodiment of a part ofthe novel erecting means shown in Fig. 1;

Fig. 3a is a top plan view of the embodiment shown in Fig. 3;

Fig. 4 is a detail vertical section of another part of the novelerecting means shown in Fig. 1;

Fig. 5 is a vertical section of a gyroscope embodying another form oferecting means of the present invention;

Fig. 5a is a top plan view of the device shown in Fig. 5;

Fig. 6 is a vertical section of an electrically driven gyroscopeembodying still another form of novel erecting means of the invention;

Fig. 6a. is a partial .top plan view of the device shown in Fig. 6;

Fig. '7 is another vertical section of a gyroscope provided with a stillfurther embodiment of the invention; and

Fig. 7a is a partial top plan view of the device shown in Fig. '7.

Referring to the drawings, and more particularly to Fig. 1, theinvention is shown therein as embodied in a gyro vertical or artificialhorizon comprising a gyroscope constituted by a fly wheel or rotor Ihaving rotation in a clockwise direction carried by or formed integrallywith a vertical shaft 5 journalled in ball bearings 4 and I6 formingpart of a casing or housing 6 which encloses the rotor I and which isuniversally suspended for angular movement about two mutuallyperpendicular horizontal axes by means of trunnions l5 secured to orformed integrally with a gimbal ring I4 which is likewise pivoted in awell known manner on trunnions perpendicular to the firstmentionedtrunnions. 1

The rotation of the gyro wheel or rotor I is produced, in the presentembodiment, by vanes provided on its periphery and against which aredirected air jets from nozzles generally located inwardly of thetrunnions I5. Instead of permitting the air which has been used fordriving the gyro rotor to escape directly into the space around theexterior of the casing 6, this air is directed through a passage 3 intoa stack-like extension 2 provided on the upper side of the casing 6.This stack-like extension is covered by a hollow drum II closed at itsupper end and journalled by means of ball bearings 8 and I3 on a. shaftI0 which is secured to or formed integral with the casing 6. The annularconnection between the lower end of the drum II and the extension 2 ismade in the form of a baiiied attachment which leaves full freedom forrotation of the drum about the shaft II] but permits only a smallquantity of air to escape.

of the drum H are coincident.

In the present embodiment, the shaft I0, about which the drum I Irotates, is shown coaxial with the rotor shaft 5 of the gyroscope sothat the axis of spin of the gyroscope and the axis of rotation Thegyroscope may be made slightly pendulous by attaching an adjustableweight 22 to the bottom side of the casing 6, said weight 22 being shownin the form of an internally threaded nut carried by a vertical screwprojecting from the bottom side of said casing ,6.

The novel erecting means of the present invention are now provided and,in the form shown, comprise air jet means illustrated as a reactionnozzle I 2 secured to or formed integrally with the drum II andprojecting radially therefrom. Thus, the nozzle I2 is adapted to beangularly adjusted and/or rotated with said drum I I about the shaft I0and, therefore, about the spin axis of the gyro rotor 1.

Acceleration responsive means are provided which are responsive toacceleration components perpendicular to the axis of rotation of thedrum .II and the rotor I for controlling the air jet means. In the formshown in Fig. 1, said acceleration responsive means comprise a mass orcounterweight I adjustably carried on a radially projecting arm securedto the drum I I, said radially projecting arm being at right angles tothe nozzle I2, and the mass or counterweight I being adjustable radiallyof the drum on said arm. Thus, it will be seen that the mass orcounterweight I and said nozzle I2 are adapted for rotation with thedrum II about the shaft I0 and, hence, about the spin axis of thegyroscope.

Since the mass I and nozzle I2 are angularly movable about the spin axisof the gyroscope, it will be apparent that when said spin axis departsfrom the vertical, said mass will tend to move into a plane containingsaid spin axis and the vertical, and will thereby angularly move thenozzle I2 so that the jet will issue from the nozzle I2 in a directionat right angles to a plane containing the spin axis of the gyroscope andthe mass I, thereby applying a torque in the gyroscope in a directionopposite to the direction in which the jet issues from the nozzle I2,this torque being produced by virtue of the reaction of said jet.

When the spin axis of the gyroscope is substantially vertical, theweight of the mass I tends to cause precession of the gyroscope in aplane perpendicular to the plane passing through the mass I and saidspin axis. This will be apparent from Fig. 1 wherein it will be seenthat the mass I, being acted upon by gravity, tends to move downwardlyto apply a torque on the gyroscope about the trunnions which areperpendicular to the trunnions I5, and this torque then causes thegyroscope to precess in a plane passing through the spin axis of thegyroscope and perpendicular to the projecting arm carrying said mass, i.e., a plane perpendicular to the plane of the paper, as viewed in Fig.l, and passing through shafts 5 and ID, i. e., through the spin axis ofthe gyroscope.

Referring to Fig. 1a, assuming that'the spin axis is caused to precessso that the top of shaft Ill moves downwardly, the mass I will likewisemove downwardly by the action of gravity, and will tend to come to restat a point 90 away in a clockwise direction, from its previous position,thereby moving the nozzle I2 to the position which was previouslyoccupied by the mass I. In other words, the drum II together with themass I and nozzle I2 will be rotated 90 in a assumes 3 clocirwisedirection as viewed in Fig. la. The -let issuing from nozzle l2 willthen issue in a direction to the right as viewed in Fig. la, therebycausing a reaction in the opposite direction,

5 namely, to the left as viewed in Fig. is. This reaction applies atorque on the gyroscope about the trunnions which are perpendicular tothe trunnions it, thus causing the gyroscope to precess haclr to itsoriginal vertical position.

W its soon as the gyroscope has been thus erected, however, thegravitational pull upon the mass l in its new position again causesprecession oi the gyroscope, thereby causing the mass i to again move bythe action oi gravity to another new position in the same direction asheiore, namely, clocliwise as viewed in Fig. la and till" away irorn itsprevious position, thereby again moving the nozzle it to a new positionin which a torque will again he applied on the gyroscope to process mthe same haclr to its vertical position. This action is reproduced in acontinuous and symmetrical manner with respect to the shafts ii and it,and, hence, with respect to the spin anis oi the gyroscope, and resultsin a continuous rotation oi the drum ii, mass i and nozzle it about thespin axis of the gyroscope, such rotation being accompanied by apseudo-nutation oi the gyroscope, the amplitude of which can he made assmall as desired by suitably proportioning the torques developed aboutthe suspension axis oi the gyroscope by the mass it and the reaction oithe nozzle ii. The continuous rotation oi the drum ii resulting in thenutation oi the gyro is (W produced by the resultant oi the two torcluesexerted by the mass and reactive iorce oi the nozzle since they producesimultaneous precessing torques.

This continuous rotation oi the mass it and nozzle it, when the spinaids oi the gyroscope is substantially vertical, balances out thereaction eiiect oi the jet issuing irom the nozzle it until such time asthe drum Iii, mass i and nozzle iii tend to stop rotating, such stoppingaction tend- W ing to occur when the spin axis oi the gyroscope iscaused to depart irom the vertical by precession due to friction in thehearings oi the rotor or due to precession caused by acceleration ordeceleration iorces acting on the pendulous gyro- W scope and producedby an increase or decrease in the dying speed oi the aircrait on whichthe gyroscope is mounted.

assuming now, ior enample, that the spin axis oi the gyroscope isdisplaced irorn the vertical due to precession oi the gyroscope byfriction in q its hearings or due to precession caused by iorces ofacceleration or deceleration acting on the gyroscopeand produced by anincrease or decrease in the ilying speed oi the aircraft on which the mgyroscope is carried, the mass II will come to rest at a point lying ina plane passing through the spin axis and the component oi the force oigravity perpendicular to said spin axis. in other words, the force oigravityacts on the mass i as to move it to a new position in a planecontaining the spin axis oi the gyroscope and the vertical, since inthat position the force oi gravity is maximum. This results in anangular adjustment oi the nozzle to a position in which it is illsubstantially perpendicular to this plane, and the air ict escaping fromthe nozzle causes a torque to he applied on the gyroscope with respectto the suspension axis of the casing t in a direction lying in a planewhich is substantially perpeni'ii dicular to the plane containing thespin axis of tilt tilt

the gyroscope and the vertical, thereby causing the gyroscope to precessback to the vertical.

When the craft upon which the gyro is mounted is caused to accelerate,the force of acceleration acts upon the mass i and also upon the 5weight it. Such acceleration force produces a precession on the part ofthe gyro, moving the mass to a new position where the acceleration iorcetends to oppose the rotation of the mass and at this point, the massbeing stationary, the is air jet applies a reactive torque sufiicient toprecess thegyro and in the proper direction to maintain the spin axis inthe vertical, provided the rotor spin is in the direction of the arrowof Figure in. it

When the transverse accelerations acting on the gyroscope are small, theprecession of the gyroscope due to the weight oi the mass It causes acontinuous rotation oi this mass always in the same direction, aspreviously indicated, and this it action may he utilized iorcompensating the frictional torque oi the shaft it in its hearings bycausing a' constant opposite torque to be applied to the gyroscope byplacing the nozzle it as shown in Fig. 2b so that the axis oi the nozzlewill he at it a small distance D from the spin axis about which thereaction oi the nozzle develops a compensating toruue.

its previously indicated, it may be advisable to matte the gyroscopeslightly pendulous in its dd e uilihri condition about the axes oi itsCardan suspension in order to iacilitate stabilization of the gyroscopewhen it is first started in operation. Then the eiiect oi thependulosity oi the gyroscope can be compensated, at least 5% partially,by positioning the nozzle it as indicated at it in do so that thenozzleiorms an obtuse angle with the radial arm which carries the mass l. inthis position, the nozzle ii is effective to produce the component oireaction in a plane containing the longitudinal axis of the nozzle iiand the radial arm on which the mass l is carried. i lnothermodification for this purpose is shown in big. id.

ltteierring to Fig. i, there is shown another form oi erecting means oithe invention in which the mass it is in the iorm oi a ball and iscaused to roll in a circular path or traclr formed by a cupshaped memberit attached to the upper side of the gyro casing i, said ball beingcarried by a 50 iorlr ii secured to or iormed integrally with a conicalmember adapted to take the place of the drum it, said conical memberalso being iormed to provide the nozzle ii. The conical member carryingthe nozzle ii is journalled on an air 55 cushion iormed between theexternal conical suriace oi said member and a cooperating conicalsuriace oi the cup-shaped member it instead of being iournalled by ballbearings as in Fig. l. The arrangement oi the mass l in this embodioment avoids the iniluence oi the weight oi said mass on the centering oithe air bearing.

in l ig. iis shown another embodiment wherein the assembly oi the nozzleii and mass it is supported by an air cushion instead oi by ball 5hearings.

instead of setting the nozzle ii radially oi the spin axis oi thegyroscope, said nozzle may he so arranged as to issue a let in adirection parallel to the spin axis oi the gyroscope, and the angular 7adjustment of the reactive force about the spin axis oi the gyroscopemay be replaced by providing means ior angularly adjusting about saidspin axis, the plane in which the reactive force is made manifest. Thus,as shown in Fig. 5, the 75 angularly adjustable nozzle l2 may comprisean aperture 12 provided in a relatively thin horizontal disc l8journalled'on the shaft H] by means of ball bearings 8 in a mannersimilar to that by which the drum II is journalled as shown in Fig. 1.The direction of rotation of the gyro rotor will be in acounterclockwise direction as indicated by the arrow of Figure 5a. Theair issuing from the aperture I2 is fed through an annular groove 20which communicates with the casing 6 by means of vents 2|. Theacceleration responsive mass l is mounted, as shown, on the upper sideof the disc I8 at the periphery of the latter, the weight of the discbeing partially supported by the pressure of the air which tends toescape from the annular groove 20, thereby considerably reducing thefriction on the supporting ball bearing 8 and thus giving a greatersensitivity to the acceleration responsive mechanism.

If desired, the gyroscope may be driven electrically instead of by air,and instead of using air pressure for causing the stabilizing orerecting action on the gyroscope, a negative pressure, i. e., a vacuum,may be used as shown in Fig. 6, for example. The direction of gyrorotation is again taken in the direction indicated by the arrow ofFigure 6a. In this latter embodiment the electricallydriven gyroscope isdesigned to also function as a fan to cause a flow of air inwardlythrough the opening I! (Fig. 6a) which is angularly adjustable by theacceleration responsive mass l, and outwardly through peripheralopenings or outlets 23 provided on the periphery of the stationary gyrocasing 6. In this embodiment the aero-dynamical reaction effect causingthe desired precession results only from the rotatable suction nozzleI2. In order to obtain precession in the proper direction in thisembodiment, assuming that the direction of rotation of the gyro rotorabout the spin axis is in a direction opposite to that in the embodimentwhich has a nozzle of the type that issues a pressure jet, thecounterweight arm should be arranged from the suction nozzle l2, theangle being measured in the same angular sense from that used inlocating the counterweight from the pressure jet nozzle.

The axis of adjustment of the erecting means, instead of being madecoincident with the spin axis of the gyroscope, may be made parallel tosaid spin axis, in which case it is advantageous to provide a pluralityof nozzles each of which is angularly adjustable about its own axisparallel to the spin axis of the gyroscope, as shown in Figs. 7 and 7a.In this embodiment, the direction of gyro rotation being in acounterclockwise direction, four similar discs 18 are provided and eachdisc carries a nozzle l2 and an acceleration responsive mass I, eachmass being adapted to angularly adjust its associated disc so that theoutlet of its associated nozzle is at right angles to the arm thatcarries the mass. In this embodiment, the erecting action of thefouracceieration responsive means is cumulative so that the sum of thereaction forces of the four nozzles exerts the desired torque to causeerective precession of the gyroscope.

Thereare thus provided simple, novel and improved erecting means forgyroscopes, and particularly for gyro verticals or artificial horizons,for returning the spin axis of the gyroscope to its normal position in aquick and effective manner.

Although several embodiments of the invention have been illustrated anddescribed, various changes in the form and relative arrangement ofparts, which will now appear to those skilled in the art, may be madewithout departing from the scope of the invention. Reference is,therefore, to be had to the appended claims for a definition of thelimits of the invention,

What is claimed is:

1. In combination, a gyroscope having three degrees of freedom, air jetmeans mounted for rotation on said gyroscope for applying a torque tosaid gyroscope about one axis thereof, and gravitational control meansconnected to and relatively fixed with respect to said air jet means fordirecting said air jet means.

2. In combination, a gyroscope having three degrees of freedom, air jetmeans for applying a torque to said gyroscope about one axis thereof,and gravitational control means connected to and relatively fixed withrespect to said air jet means mounted for rotation about another axis ofsaid gyroscope for controlling said air jet means.

3. A' gyroscopic apparatus comprising a universally supported gyroscope,means for exerting an erecting torque on said gryoscope during deviationthereof from its normal position, said erecting means comprising aplurality of air jet means mounted for rota-tion on the gyroscope, andgravity controlled means connected to and relatively fixed with respectto said air jet means for controlling said air jet means.

4. A gyroscopic apparatus comprising a universally supported gyroscope,and means for exerting an erecting torque on said gyroscope duringdeviation thereof from its normal position, said erecting meanscomprising air jet means mounted for rotation on the gyroscope, andacceleration responsive means connected to and relatively fixed withrespect to said air jet means for rotating said air jet means.

5. A gyro vertical or artificial horizon comprising a gyroscope having arotor mounted for rotation about a vertical axis and for angularmovement about two mutually perpendicular horizontal axes, a housing forsaid rotor, air jet means mounted for rotation about an axis parallel tothe spin axis of said rotor and arranged to produce a reactive force ina direction per-

